Only Up can be played on the Steam platform. The following are the specific steps:
If you don't have Steam, visit the official Steam website and click "Install Steam" in the upper right corner to download and install the platform.
After downloading and installing, open Steam and register an account to log in.
In the store search bar, type "Only Up" and press Enter.
Locate the Only Up game in the search results, purchase it, and then you can download and start playing.